Depending on what you're doing, you might still want to take a look at 8051 family of chips. They have timers, serial ports, built-in oscilator, hardware interrupts, and many features that make them ideal for microcontoller projects. If you know 8080 Assembly language, the transition to 8051 should not be hard.

As I've said, I'm playing around with the 8052, and it's really not difficult. It's actually kiond of nice that there are so many resources - compilers, assemblers, etc. - available for free, as well as many support sites.

Your post is old, but it just now caught my eye... hope I can help. There is a store, or at least there used to be (lol) called "The Electronics Barn" in Bloomfield, New Jersey USA... they sold used 2nd-hand electronic equipment (radios, pc's, etc..) and had a huge supply of old 8088, 8086 (and others) motherboards and loose chips. I've checked on the web to see if they're online, but no. You might want to call the phone company for information and see if you can get their phone number... and if so, give them a call.

Good luck,Alan

: does anyone know if the source code for the 8086/88 is compatible with the 8051 ?: : and... would anyone know where to find some basic schematics of 8086 circuits ?: : thanks:

: does anyone know if the source code for the 8086/88 is compatible with the 8051 ?: : and... would anyone know where to find some basic schematics of 8086 circuits ?: : thanks:

Hello, I know your message is old but if you are still interested here is some info that may be of help.The 8086 is really an old PC style processor (is it still available ?) and a bit of a dinosaur ! You wouldn't really want to use it as the processing core of an embedded system.The 8051 family is the industry standard 'single chip processor' and totally suited for (simple) embedded applications, provided you don't need more that 8 bit data, ie, no complicated maths, etc.I have used the 8051 in one form or another for a great many real-time control projects from energy efficient heating control to CCTV cameras and can recommend it to you without reservation. It also has serial comms on board (UART) so you can do inter-processor comms, talk to a PC or lap-top, etc, which may be useful.There are lots of tools available too, as it is widely used.Other than that there are several small AVR chips with the RISC instruction set which is very simple to learn. These tend to run a bit quicker (more efficient) than the '51 (whose top speed is limited!) because of the architecture of the core.One tip is ..... get yourself a good 'C' compiler as doing it in assembler (unless absolutely necessary) is a waste of time these days and its not transportable so you don't have the option to switch processors (which C gives you) say, if your processor went obsolete.

: Hi Gordon!: : I've been wanting to do a furnace controller for my home for a long time. Is that what you did?: : I'd even be happy with a device that monitors which thermostat is active, and the length of time the furnace runs.: : I could do all this from scratch, but if you've already done it...: : Maybe you can save me a bit of work?: : Thanks!: :: : [purple]Melissa[/purple]: : Hi Melissa,

I think what I did (quite some time ago now!) may be a bit over complicated as the product was really intended for large building (office, factory, etc) control where you can really save a lot of money but ... you can do something similar with the technology. This is what it was ;

A Timeswitch to program On/Off heating cycles during the day,An 'Optimiser' to 'learn' the heating and cooling characteristics of the building and adjust the timeswitch 'start and end' times so that the inside temperature is/will still be at the desired during the period (ie, if you can switch off early... do it!),A 'compensator' to calculate the right water temperature based on inside and outside temperature,Proportional/Integral Control of either a motorised (pulsed) valveor direct boiler (furnace?) control (on/off),Frost protection,Pump 'run on'.

The display was LED digits (it gets dark down in the boiler-room).

There are up to 4 temperature sensors required, a lot of electronics and quite a bit of installation !

I probably have some/all of the code (stored away somewhere on very old media which might be a problem now!), I can't guarantee circuits but you might want to update some of the devices anyway.If you like I'll see what I still have.

I wanted to do a residential version, with water temp sensors, and thermostat sensors.

What I'd like to do is to monitor the thermostat for a particular zone, and gather data on things like how long it takes for the radiator to become warm in that zone, how long it runs for a given start-stop temp, etc.

It seems to me that there's residual heat in the water and boiler even after the zone stops calling for heat. What I was thinking was that the pump would continue running (if that was the last/only zone that had been calling for heat) until the temp of the water got below the optimum transfer temp.

It sounds complicated, but once I get a few water sensors installed, the rest would be just playing with the code. I'd actually like to just monitor it all for a while, to see what's going on. Then tackle trying to control it.

We've also got a situation where we have to run water at a faucet for a while until it becomes hot. One bathroom in particular is very far away from the water heater. Since we pay to pump the water out of the ground (we have a well) and we pay to put it back into the ground (we have an electrically pumped septic system), it seems like a waste to do this.

So, I'd like to have the controller circulate the water to the faucet until it becomes warm. But i'd like to do this only when it's likely that the hot water's being used, to minimize heat loss during circulation. We already have the plumbing installed for the loop, so we'd just have to get a circulator and some type of controller for it.

: Sounds interesting.: : I wanted to do a residential version, with water temp sensors, and thermostat sensors.: : What I'd like to do is to monitor the thermostat for a particular zone, and gather data on things like how long it takes for the radiator to become warm in that zone, how long it runs for a given start-stop temp, etc.: : It seems to me that there's residual heat in the water and boiler even after the zone stops calling for heat. What I was thinking was that the pump would continue running (if that was the last/only zone that had been calling for heat) until the temp of the water got below the optimum transfer temp.: : It sounds complicated, but once I get a few water sensors installed, the rest would be just playing with the code. I'd actually like to just monitor it all for a while, to see what's going on. Then tackle trying to control it.: : We've also got a situation where we have to run water at a faucet for a while until it becomes hot. One bathroom in particular is very far away from the water heater. Since we pay to pump the water out of the ground (we have a well) and we pay to put it back into the ground (we have an electrically pumped septic system), it seems like a waste to do this.: : So, I'd like to have the controller circulate the water to the faucet until it becomes warm. But i'd like to do this only when it's likely that the hot water's being used, to minimize heat loss during circulation. We already have the plumbing installed for the loop, so we'd just have to get a circulator and some type of controller for it.: : Now, honestly. Do I sound like someone who needs a hobby? : : : : : [purple]Melissa[/purple]: :

Hi Melissa,

It sounds like what you want to do is 'Pump Overrun'. Most heating systems do this anyway by running the pump on for a few minutes (set time) after the heating goes off, as yes, there is residual heat in the system. How long that heat stays there is dependent on the cooling characteristic (fabric) of your building and the current outside temperature.The easy way to do it is to run the pump until the water temp. hits about 2 or 3 degrees C below the calculated target (the temp. you measured at switch off). What sort of sensors will you use ? Be aware that some types of sensor (i.e., thermistors) are non-linear and you may need to convert the readings with a 'look-up' table.

As to the other problem, could you use a simple movement detector (really cheap from the local DIY store, used to activate security lights) to sense when someone is in the bathroom (and likely to need hot water) and start a small pump circulating ??

: : Sounds interesting.: : : : I wanted to do a residential version, with water temp sensors, and thermostat sensors.: : : : What I'd like to do is to monitor the thermostat for a particular zone, and gather data on things like how long it takes for the radiator to become warm in that zone, how long it runs for a given start-stop temp, etc.: : : : It seems to me that there's residual heat in the water and boiler even after the zone stops calling for heat. What I was thinking was that the pump would continue running (if that was the last/only zone that had been calling for heat) until the temp of the water got below the optimum transfer temp.: : : : It sounds complicated, but once I get a few water sensors installed, the rest would be just playing with the code. I'd actually like to just monitor it all for a while, to see what's going on. Then tackle trying to control it.: : : : We've also got a situation where we have to run water at a faucet for a while until it becomes hot. One bathroom in particular is very far away from the water heater. Since we pay to pump the water out of the ground (we have a well) and we pay to put it back into the ground (we have an electrically pumped septic system), it seems like a waste to do this.: : : : So, I'd like to have the controller circulate the water to the faucet until it becomes warm. But i'd like to do this only when it's likely that the hot water's being used, to minimize heat loss during circulation. We already have the plumbing installed for the loop, so we'd just have to get a circulator and some type of controller for it.: : : : Now, honestly. Do I sound like someone who needs a hobby? : : : : : : : : : : [purple]Melissa[/purple]: : : : : : Hi Melissa,: : It sounds like what you want to do is 'Pump Overrun'. Most heating systems do this anyway by running the pump on for a few minutes (set time) after the heating goes off, as yes, there is residual heat in the system. How long that heat stays there is dependent on the cooling characteristic (fabric) of your building and the current outside temperature.: The easy way to do it is to run the pump until the water temp. hits about 2 or 3 degrees C below the calculated target (the temp. you measured at switch off). What sort of sensors will you use ? Be aware that some types of sensor (i.e., thermistors) are non-linear and you may need to convert the readings with a 'look-up' table.: : As to the other problem, could you use a simple movement detector (really cheap from the local DIY store, used to activate security lights) to sense when someone is in the bathroom (and likely to need hot water) and start a small pump circulating ??: : Regards GS.: Hi Gordon and Melissa:I am using a Rigel development board based on the Dallas Semi 80c320 and am interfacing it to our motorhome. So far I have hooked it to my GPS and electronically log our travels to battery backed RAM, Once every minute it logs our latitude, logitude, altitude and time. I have also built a fancy NICAD battery charger that uses the A2D converter to completely discharge each individual cell before charging it at a constant current.Current project is modifying the monitor to add additional functionality in the form of subroutines I can call.Lots of fun and it keeps me out of the bars.Regards,Geof